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I have been wanting to post this build idea for a bit and just got some time tonight to get it all together. It is a amazing option for those that want a very powerful 470nm+ build without breaking the bank. It is super easy to put together and so far I have not found a limit to the duty cycle.

This build is possible due to the new 20mm adapters from Survival Lasers for use with their hosts and a custom NDB7675 20mm module that is driven with a 2.8A blackbuck driver I will be offering. Uses the full copper 20mm with driver shelf in the back half to both thermally bond the driver and keep the diode nice and stable with this current. This makes an amazing super bright sky blue color and my favorite units that I have right now. Puts out over 2W and while I don't have a spectro testing in the NDB7675 spectro threads show over 470nm with 2.8A.

You will also need batteries. Suggest two AW IMR 18350's. Show pictures of two AW IMR 16340's thinking the 18350's would not fit but they do fit great.

The best part about this is the duty cycle with the 20mm module. I have not found a limit that I would not pass yet. I ran it for more than 5 minutes at a time quite a few times while taking pictures and it was only moderately warm. These sinks are amazing.

So here are all the parts laid out.

Here is the driver pill and contact board with ring.

Start by clipping the leads from the module about an inch and a half from the module. Strip about 1 mm of the leads and put some flux on the exposed wire. Slide the drilled pill on followed by the retaining ring.

Next solder the leads to the positive and neagative contact points on the contact board.

Pinch the board in the retaining ring.

Pinch the retaining ring with board into the drilled pill.

Screw the pill into the host body.

Next is really the only step to be careful on. Screw on the 20mm adapter but do so holding the module with your finger so it does not spin as you screw down the head. it is ok if there is a little spin right at the end but if allowed to spin the whole time it can rip the wires out or the driver board off its mount.

Then you are all done. Pop in your batteries and you are ready to go.:eg:

I haven't heard much feedback about longevity with highly pushed 7675's.. given the number of people that seemed to be doing this, I'm surprised to come up short in a search for long term reliability reports, or mentions of failures or degradation on those pushed builds. Given the price of these diodes, it honestly doesn't matter to me if they don't make it past 500 hours, easily a solid $59 worth of photon induced wetness, but if there's no indication of early failures and no noticeable drop in output from ageing builds it's all the more attractive.

Yea I was not a fan of it then. This is still pushing the diode beyond foldback but back then we did not even have the 12mm copper back halfs yet and the heat could only escape via the edge of the diode base. The diodes were not running stable and the heat build up was immense. Pulling heat form the base of the diode and being in the new 20mm modules it seems to be drawing the heat away from the diode effectively.

Yes price is also a factor. They were quite expensive then. They certainly will only last a fraction of the datasheet 20K hour expected life but in a portable that is still a very long time. Also comparing to say buying a 80mW 470nm diode for $500 this is great.

Well-known member

Yea I was not a fan of it then. This is still pushing the diode beyond foldback but back then we did not even have the 12mm copper back halfs yet and the heat could only escape via the edge of the diode base. The diodes were not running stable and the heat build up was immense. Pulling heat form the base of the diode and being in the new 20mm modules it seems to be drawing the heat away from the diode effectively.

Yes price is also a factor. They were quite expensive then. They certainly will only last a fraction of the datasheet 20K hour expected life but in a portable that is still a very long time. Also comparing to say buying a 80mW 470nm diode for $500 this is great.

All good! This Custom build I did is even better than the screw in back halfs, the modules only have a lip that sits on the diode back were I always remove that lip and have the back half sit flush, also whole module is pressed in with vice so the whole host is extracting the heat.

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I have two of these diodes and was planning on driving them at 2.4 amps. Now, I have a question. How do you press the diodes into the 20mm module adapter? If I am going to push these to 2.7 amps, I'll want the 20mm modules and a way to successfully press the diode into it. Thanks for the great tutorial and a new idea I hadn't thought of.

Well-known member

Very nice build tutorial DTR, the S/L C6 host & 20mm adapter are a good match up for your Overdrive Special project! :beer:
Now, all we have to do is get Gary to make a 25mm adapter for the C6, for even more heatsinking capability!
:gj: +rep!